Functionalized heteroacenes and electronic devices generated therefrom

ABSTRACT

An electronic device, such as a thin film transistor containing a semiconductor of, for example, of the Formula (I) 
                         
wherein R represents alkyl, alkoxy, aryl, heteroaryl or a suitable hydrocarbon; each R 1  and R 2  is independently hydrogen (H), a suitable hydrocarbon; a heteroatom containing group or a halogen; R 3  and R 4  are independently a suitable hydrocarbon, a heteroatom containing group, or a halogen; x and y represent the number of groups; Z represents sulfur, oxygen, selenium, or NR′ wherein R′ is hydrogen, alkyl, or aryl; and n and m represent the number of repeating units.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The electronic devices and certain components thereof were supported bya United States Government Cooperative Agreement No. 70NANBOH3033awarded by the National Institute of Standards and Technology (NIST).The United States Government has certain rights relating to the devicesand certain semiconductor components illustrated hereinafter.

CROSS REFERENCE TO RELATED APPLICATIONS

U.S. application Ser. No. 11/399,226, filed concurrently herewith, onFunctionalized Heteroacenes, by Yuning Li et al.

U.S. application Ser. No. 11/399,216, filed concurrently herewith, onPolyacenes and Electronic Devices Generated Therefrom, by Yuning Li etal.

U.S. application Ser. No. 11/399,064, filed concurrently herewith, onHeteroacene Polymers and Electronic Devices Generated Therefrom, byYuning Li et al.

U.S. application Ser. No. 11/399,169, filed concurrently herewith, onEthynylene Acene Polymers and Electronic Devices Generated Therefrom, byYuning Li et al.

U.S. application Ser. No. 11/399,091, filed concurrently herewith, onEthynylene Acene Polymers, by Yuning Li et al.

U.S. application Ser. No. 11/399,231, filed concurrently herewith, onPoly[bis(ethynyl)heteroacenes] and Electronic Devices GeneratedTherefrom, by Yuning Li et al.

U.S. application Ser. No. 11/399,141, filed concurrently herewith, onSemiconductors and Electronic Devices Generated Therefrom, by Yiliang Wuet al.

U.S. application Ser. No. 11/399,230, filed concurrently herewith, onSemiconductor Polymers, by Yiliang Wu et al.

U.S. application Ser. No. 11/399,941, filed concurrently herewith, onPolydiazaacenes and Electronic Devices Generated Therefrom, by YiliangWu et al.

U.S. application Ser. No. 11/399,092, filed concurrently herewith, onPolydiazaacenes, by Yiliang Wu et al.

U.S. application Ser. No. 11/398,931, filed concurrently herewith, onPoly(alkynylthiophene)s and Electronic Devices Generated Therefrom, byBeng S. Ong et al.

U.S. application Ser. No. 11/399,246, filed concurrently herewith, onPoly(alkynylthiophene)s, by Beng S. Ong et al.

U.S. application Ser. No. 11/399,092, filed concurrently herewith, onLinked Arylamine Polymers and Electronic Devices Generated Therefrom, byYuning Li et al.

U.S. application Ser. No. 11/399,065, filed concurrently herewith, onLinked Arylamine Polymers, by Yuning Li et al.

Illustrated in U.S. application Ser. No. 11/011,678 filed Dec. 14, 2004,now abandoned, relating to indolocarbazole moieties and thin filmtransistor devices thereof.

Illustrated in U.S. application Ser. No. 11/167,512 filed Jun. 27, 2005,U.S. Publication 20060214155, relating to indolocarbazole moieties andthin film transistor devices thereof.

Illustrated in U.S. Pat. No. 6,770,904 and copending application U.S.application Ser. No. 10/922,662, Publication No. 20050017311, areelectronic devices, such as thin film transistors containingsemiconductor layers of, for example, polythiophenes.

The disclosure of each of the above cross referenced applications andpatent is totally incorporated herein by reference. In aspects of thepresent disclosure, there may be selected the appropriate substituents,such as a suitable hydrocarbon, a heteroatom containing group, hydrogen,halogen, CN, NO₂, rings, number of repeating polymer units, number ofgroups, and the like as illustrated in the copending applications.

The appropriate components, processes thereof and uses thereofillustrated in these copending applications and patents may be selectedfor the present invention in embodiments thereof.

BACKGROUND

The present disclosure is generally directed to polymers and usesthereof. More specifically, the present disclosure in embodiments isdirected to a class of heteroacenes functionalized with, for example,alkylethynyl or alkylarylethynyl groups, and other suitable groups asillustrated herein, and which components can be selected as solutionprocessable and substantially stable channel semiconductors in organicelectronic devices, such as thin film transistors.

There are desired electronic devices, such as thin film transistors,TFTs, fabricated with the polymers illustrated herein, such asfunctionalized heteroacenes with excellent solvent solubility, which canbe solution processable; and devices with mechanical durability andstructural flexibility, which may be highly desirable for fabricatingflexible TFTs on plastic substrates. Flexible TFTs would enable thedesign of electronic devices which usually involve structuralflexibility and mechanical durability characteristics. The use ofplastic substrates together with the functionalized heteroacenecomponents can transform the traditionally rigid silicon TFT into amechanically more durable and structurally flexible TFT design. This isof particular value to large area devices, such as large-area imagesensors, electronic paper and other display media. Also, the selectionof functionalized heteroacenes TFTs for integrated circuit logicelements for low end microelectronics, such as smart cards, radiofrequency identification (RFID) tags, and memory/storage devices, mayenhance their mechanical durability, and thus their useful life span.

A number of semiconductor materials are not, it is believed, stable whenexposed to air as they become oxidatively doped by ambient oxygen,resulting in increased conductivity. The result is a large off-currentand thus a low current on/off ratio for the devices fabricated fromthese materials. Accordingly, with many of these materials, rigorousprecautions are usually undertaken during materials processing anddevice fabrication to exclude environmental oxygen to avoid or minimizeoxidative doping. These precautionary measures increase the cost ofmanufacturing therefore offsetting the appeal of certain semiconductorTFTs as an economical alternative to amorphous silicon technology,particularly for large area devices. These and other disadvantages areavoided or minimized in embodiments of the present disclosure.

REFERENCES

Heteroacenes are known to possess acceptable high field effect mobilitywhen used as channel semiconductors in TFTs. However, these materialsare rapidly oxidized by, for example, atmospheric oxygen under light,and such materials are not considered processable at ambient conditions.Furthermore, heteroacenes, when selected for TFTs, have poor thin filmformation characteristics, and are substantially insoluble or haveminimal solubility in a number of commonly used solvents rendering thesecompounds as being nonsolution processing; accordingly, such compoundshave been mostly processed by vacuum deposition methods that result inhigh production costs, and which disadvantages are eliminated orminimized with the TFTs generated with the functionalized heterocenesillustrated herein.

A number of organic semiconductor materials has been described for usein field effect TFTs, which materials include organic small moleculessuch as pentacene, see for example D. J. Gundlach et al., “Pentaceneorganic thin film transistors—molecular ordering and mobility”, IEEEElectron Device Lett., Vol. 18, p. 87 (1997); oligomers, such assexithiophenes or their variants, see for example reference F. Gamier etal., “Molecular engineering of organic semiconductors: Design ofself-assembly properties in conjugated thiophene oligomers”, J. Amer.Chem. Soc., Vol. 115, p. 8716 (1993), and certain functionalizedheteroacenes, such as poly(3-alkylthiophene), see for example referenceZ. Bao et al., “Soluble and processable regioregularpoly(3-hexylthiophene) for field-effect thin film transistor applicationwith high mobility”, Appl. Phys. Lett. Vol. 69, p 4108 (1996). Althoughorganic material based TFTs generally provide lower performancecharacteristics than their conventional silicon counterparts, such assilicon crystal or polysilicon TFTs, they may nonetheless besufficiently useful for applications in areas where high mobility is notrequired. These devices may include large area devices, such as imagesensors, active matrix liquid crystal displays and low endmicroelectronics, such as smart cards and RFID tags.

TFTs fabricated from the polymers illustrated herein, such asfunctionalized heteroacenes, may be functionally and structurally moredesirable than conventional silicon technology in that they may offermechanical durability, while also avoiding vacuum deposition, structuralflexibility, and the potential of being able to be incorporated directlyonto the active media of the devices thus enhancing device compactnessfor transportability.

With vacuum deposition, it is difficult to achieve consistent thin filmquality for large area formats. Polymer TFTs, such as those fabricatedfrom regioregular components, of, for example, regioregularpoly(3-alkylthiophene-2,5-diyl) by solution processes, while offeringsome mobility, suffer from their propensity toward oxidative doping inair. For practical low cost TFT design, it is therefore of value to havea semiconductor material that is both stable and solution processable,and where its performance is not adversely affected by ambient oxygen,for example, TFTs generated with poly(3-alkylthiophene-2,5-diyl) arevery sensitive to air. The TFTs fabricated from these materials inambient conditions generally exhibit very large off-current, very lowcurrent on/off ratios, and their performance characteristics degraderapidly.

Illustrated in Huang, D. H., et al, Chem. Mater. 2004, 16, 1298-1303,are, for example, LEDS and field effect transistors based on certainphenothiaazines like poly(10-(2-ethylhexyl)phenothiaazine).

Illustrated in Zhu, Y., et al, Macromolecules 2005, 38, 7983-7991, are,for example semiconductors based on phenoxazine conjugated polymers likepoly(10-hexylphenoxazine).

Additional references that may be of interest include U.S. Pat. Nos.6,150,191; 6,107,117; 5,969,376; 5,619,357, and 5,777,070, thedisclosures of which are totally incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrated in FIGS. 1 to 4 are various representative embodiments ofthe present disclosure, and wherein polymers like functionalizedheteroacenes are selected as the channel or semiconductor material inthin film transistor (TFT) configurations.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

It is a feature of the present disclosure to provide polymersemiconductors, which are useful in microelectronic device applications,such as TFT devices.

It is another feature of the present disclosure to providefunctionalized heteroacenes with a band gap of from about 1.5 eV toabout 3 eV as determined from the absorption spectra of thin filmsthereof, and which functionalized heteroacenes are suitable for use asTFT semiconductor channel layer materials.

In yet a further feature of the present disclosure there are providedfunctionalized heteroacenes which are useful as microelectroniccomponents, and which functionalized heteroacenes possess solubility of,for example, at least about 0.1 percent to about 95 percent by weight incommon organic solvents, such as methylene chloride, tetrahydrofuran,toluene, xylene, mesitylene, chlorobenzene, and the like, and thus thesecomponents can be economically fabricated by solution processes such asspin coating, screen printing, stamp printing, dip coating, solutioncasting, jet printing, and the like.

Another feature of the present disclosure resides in providingelectronic devices, such as TFTs, with a functionalized heteroacenechannel layer, and which layer has a conductivity of from about 10⁻⁴ toabout 10⁻⁹ S/cm (Siemens/centimeter).

Also, in yet another feature of the present disclosure there areprovided novel polymers like functionalized heteroacenes and devicesthereof, and which devices exhibit enhanced resistance to the adverseeffects of oxygen, that is, these devices exhibit relatively highcurrent on/off ratios, and their performance does not substantiallydegrade as rapidly as similar devices fabricated with regioregularpoly(3-alkylthiophene-3,5-diyl) or with heteroacenes.

Additionally, in a further feature of the present disclosure there isprovided a class of novel polymers like functionalized heteroacenes withunique structural features, which are conducive to molecularself-alignment under appropriate processing conditions, and whichstructural features also enhance the stability of device performance.Proper molecular alignment can permit higher molecular structural orderin thin films, which can be important to efficient charge carriertransport, thus higher electrical performance.

There are disclosed in the embodiments, polymers like functionalizedheteroacenes and electronic devices thereof. More specifically, thepresent disclosure relates to polymers illustrated by or encompassed byFormula (I)

wherein R represents a suitable hydrocarbon like alkyl, aryl, orheteroaryl; each R₁ and R₂ is independently hydrogen (H), a suitablehydrocarbon; a heteroatom containing group or a halogen; R₃ and R₄ areindependently a suitable hydrocarbon, a heteroatom containing group, ora halogen; x and y represent the number of groups; Z represents sulfur,oxygen, selenium, or NR′ wherein R′ is hydrogen, alkyl, or aryl; m and neach represent the number of rings, such as for example from zero (0) toabout 3; and more specifically, x and y can be, for example, from zeroto about 12, and more specifically, wherein each x and y are from about3 to about 7.

Examples of alkyl with, for example, from about 1 to about 30, includingfrom about 4 to about 18 carbon atoms (included throughout are numberswithin the range, for example 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17 and 18), and further including from about 6 to about 16 carbonatoms are butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl,dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl,octadecyl, nonadecyl, or eicosanyl, isomeric forms thereof, mixturesthereof, and the like; alkylaryl with from about 7 to about 49 carbonatoms, from about 6 to about 37 carbon atoms, from about 13 to about 25carbon atoms, such as methyl phenyl, substituted phenyls, and the like;or aryl, such as phenyl with about 6 to about 48 carbon atoms.

Heteroatom containing groups include, for example, polyethers,trialkylsilyls, heteroaryls, and the like; and more specifically,thienyl, furyl and pyridiaryl. The hetero component can be selected froma number of known atoms like sulfur, oxygen, nitrogen, silicon,selenium, and the like.

In embodiments, R can be an unbranched alkyl of, for example, from about2 to about 16 carbon atoms; an unbranched alkylaryl where alkylcontains, for example, from about 4 to about 12 carbon atoms; R₁ and R₁₂are hydrogen, alkyl, aryl, halogen, cyano, nitro, and the like; m and nare each zero, or from 1 to about 3; and x and y are each zero, or from1 to about 12.

Hydrocarbons are known and include alkyl, alkoxy, aryl, alkylaryl,substituted alkyl, alkoxy, aryl, and the like. Specific illustrativeexamples are

wherein R₅ is, for example, a hydrocarbon of methyl, ethyl, propyl,butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl,tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, or octadecyl;trifluoromethyl, fluoroethyl, perfluoropropyl, perfluorobutyl,perfluoropentyl, perfluorohexyl, perfluoroheptyl, perfluorooctyl,perfluorononyl, perfluorodecyl, perfluoroundecyl, or perfluorododecyl;phenyl, methylphenyl (tolyl), ethylphenyl, propylphenyl, butylphenyl,pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl,decylphenyl, undecylphenyl, dodecylphenyl, tridecylphenyl,tetradecylphenyl, pentadecylphenyl, hexadecylphenyl, heptadecylphenyl,octadecylphenyl, trifluoromethylphenyl, fluoroethylphenyl,perfluoropropylphenyl, perfluorobutylphenyl, perfluoropentylphenyl,perfluorohexylphenyl, perfluoroheptylphenyl, perfluorooctylphenyl,perfluorononylphenyl, perfluorodecylphenyl, perfluoroundecylphenyl, orperfluorododecylphenyl; and wherein X is F, Cl, Br, CN, or NO₂.

The polymers, such as the functionalized heteroacenes, in embodimentsare soluble or substantially soluble in common coating solvents, forexample, in embodiments they possess a solubility of at least about 0.1percent by weight, and more specifically, from about 10 percent to about95 percent by weight in such solvents as methylene chloride,1,2-dichloroethane, tetrahydrofuran, toluene, xylene, mesitylene,chlorobenzene, dichlorobenzene, and the like. Moreover, thefunctionalized heteroacenes of the present disclosure in embodimentswhen fabricated as semiconductor channel layers in TFT devices provide astable conductivity of, for example, from about 10⁻⁹ S/cm to about 10⁻⁴S/cm, and more specifically, from about 10⁻⁸ S/cm to about 10⁻⁵ S/cm asdetermined by conventional four-probe conductivity measurements.

It is believed that the polymers when fabricated from solutions as thinfilms, for example, of from about 10 nanometers to about 500 nanometersor from about 100 to about 300 nanometers in thickness materials aremore stable in ambient conditions than similar devices fabricated fromheteroacenes. When unprotected, the aforementioned polymer materials anddevices are generally stable for a number of weeks rather than days orhours as is the situation with poly(3-alkylthiophene-2,5-diyl) afterexposure to ambient oxygen, thus the devices fabricated from thefunctionalized heteroacenes in embodiments of the present disclosure canprovide higher current on/off ratios, and their performancecharacteristics do not substantially change as rapidly as that ofnonfunctionalized heteroacenes, or than poly(3-alkylthiophene-2,5-diyl)when no rigorous procedural precautions have been taken to excludeambient oxygen during material preparation, device fabrication, andevaluation. The functionalized heteroacenes stability of the presentdisclosure in embodiments against oxidative doping, particularly for lowcost device manufacturing, does not usually have to be handled in aninert atmosphere, and the processes thereof are, therefore, simpler andmore cost effective, and the fabrication thereof can be applied to largescale production processes.

The preparation of functionalized heteroacenes of the present disclosurecan be generally accomplished as illustrated herein. More specifically,one process of preparation is illustrated in Scheme 1.

5,11-Decynylanthra[2,3-b:6,7-b′]dithiophene/5,11-decynylanthra[2,3-b:7,6-b′]dithiophene(1a, a mixture of trans and cis isomers) and5,11-bis(4-phenylethynyl)anthra[2,3-b:6,7-b′]dithiophene/5,11-bis(4-phenylethynyl)anthra[2,3-b:7,6-b′]dithiophene(8a, a mixture of trans and cis isomers) can be generated as shown inScheme 1. First, 1-decyne (available from Sigma-Aldrich) is reacted withabout 1 molar equivalent of isopropylmagnesium chloride (available fromSigma-Aldrich) in tetrahydrofuran (THF) at elevated temperatures of, forexample, 60° C. for a suitable period like 30 minutes. Then to thereaction mixture is addedanthra[2,3-b:6,7-b′]dithiophene-5,11-dione/anthra[2,3-b:7,6-b′]dithiophene-5,11-dione(a mixture of trans and cis isomers) (this starting material is preparedaccording to De la Cruz, P., et al, J. Org. Chem. 1992, 57, 6192)followed by stirring at elevated temperatures of, for example, 60° C.for a suitable period like 1 hour. Finally, tin (II) chloride (SnCl₂)solution in 10 percent HCl is added to the reaction mixture and stirredat elevated temperatures of, for example, 60° C. for a suitable periodlike 30 minutes. After work up and recrystallization, the substantiallypure compound 1a is obtained. Compound 8a is prepared similarly startingfrom 1-ethynyl-4-pentylbenzene (available from Sigma-Aldrich) instead of1-decyne.

Aspects of the present disclosure relate to an electronic devicecontaining the functionalized heteroacenes illustrated herein; a devicewhich is a thin film transistor comprised of a substrate, a gateelectrode, a gate dielectric layer, a source electrode and a drainelectrode, and in contact with the source/drain electrodes and the gatedielectric layer, a semiconductor layer comprised of the functionalizedheteroacenes illustrated herein, and more specifically, an electronicdevice comprising a semiconductive material containing a component ofFormula (I)

wherein R represents alkyl, aryl, or heteroaryl; each R₁ and R₂ isindependently hydrogen (H), a suitable hydrocarbon, a heteroatomcontaining group or a halogen; R₃ and R₄ are independently a suitablehydrocarbon, a heteroatom containing group, or a halogen; x and yrepresent the number of groups; Z represents sulfur, oxygen, selenium,or NR′ wherein R′ is hydrogen, alkyl, or aryl; and n and m represent thenumber of repeating units; a thin film transistor comprised of asubstrate, a gate electrode, a gate dielectric layer, a source electrodeand a drain electrode, and in contact with the source/drain electrodesand the gate dielectric layer a semiconductor layer comprised ofcomponents of the formula

wherein R represents a hydrocarbon; each R₁ and R₂ is independentlyhydrogen (H), a suitable hydrocarbon; a heteroatom containing group or ahalogen; R₃ and R₄ are independently a suitable hydrocarbon, aheteroatom containing group, or a halogen; x, and y represent the numberof groups; Z represents sulfur, oxygen, selenium, or NR′ wherein R′ ishydrogen, alkyl, or aryl; and m and n represent the number of rings; athin film transistor comprised of a substrate, a gate electrode, a gatedielectric layer, a source electrode, a drain electrode and a layer of afunctionalized heteroacene of the formulas

wherein R₅ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl,octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,hexadecyl, heptadecyl, or octadecyl; trifluoromethyl, fluoroethyl,perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl,perfluoroheptyl, perfluorooctyl, perfluorononyl, perfluorodecyl,perfluoroundecyl, or perfluorododecyl; phenyl, methylphenyl (tolyl),ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl,heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl,dodecylphenyl, tridecylphenyl, tetradecylphenyl, pentadecylphenyl,hexadecylphenyl, heptadecylphenyl, octadecylphenyl,trifluoromethylphenyl, fluoroethylphenyl, perfluoropropylphenyl,perfluorobutylphenyl, perfluoropentylphenyl, perfluorohexylphenyl,perfluoroheptylphenyl, perfluorooctylphenyl, perfluorononylphenyl,perfluorodecylphenyl, perfluoroundecylphenyl, or perfluorododecylphenyl;and wherein X is F, Cl, Br, CN, or NO₂; a polymer of theformula/structure

wherein R represents alkyl, aryl, or heteroaryl; each R₁ and R₂ isindependently hydrogen (H), a suitable hydrocarbon; a heteroatomcontaining group or a halogen; R₃ and R₄ are independently a suitablehydrocarbon, a heteroatom containing group, or a halogen; x and yrepresent the number of groups; Z represents sulfur, oxygen, selenium,or NR′ wherein R′ is hydrogen, alkyl, or aryl; and n and m represent thenumber of repeating unit; a TFT device wherein the substrate is aplastic sheet of a polyester, a polycarbonate, or a polyimide; the gatesource and drain electrodes are each independently comprised of gold,nickel, aluminum, platinum, indium titanium oxide, or a conductivepolymer, and the gate dielectric is a dielectric layer comprised ofsilicon nitride or silicon oxide; a TFT device wherein the substrate isglass or a plastic sheet; said gate, source and drain electrodes areeach comprised of gold, and the gate dielectric layer is comprised ofthe organic polymer poly(methacrylate), or poly(vinyl phenol); a devicewherein the functionalized heteroacene layer is formed by solutionprocesses of spin coating, stamp printing, screen printing, or jetprinting; a device wherein the gate, source and drain electrodes, thegate dielectric, and semiconductor layers are formed by solutionprocesses of spin coating, solution casting, stamp printing, screenprinting, or jet printing; and a TFT device wherein the substrate is aplastic sheet of a polyester, a polycarbonate, or a polyimide, and thegate, source and drain electrodes are fabricated from the organicconductive polymer polystyrene sulfonate doped poly(3,4-ethylenedioxythiophene), or from a conductive ink/paste compound of a colloidaldispersion of silver in a polymer binder, and the gate dielectric layeris organic polymer or inorganic oxide particle-polymer composite; anddevice or devices include electronic devices such as TFTs.

DETAILED DESCRIPTION OF THE FIGURES

In FIG. 1 there is schematically illustrated a TFT configuration 10comprised of a substrate 16, in contact therewith a metal contact 18(gate electrode), and a layer of an insulating dielectric layer 14 withthe gate electrode having a portion thereof or the entire gate incontact with the dielectric layer 14 on top of which layer 14 two metalcontacts, 20 and 22 (source and drain electrodes), are deposited. Overand between the metal contacts 20 and 22 is the polymer layer 12 of5,11-decynylanthra[2,3-b:6,7-b′]dithiophene/5,11-decynylanthra[2,3-b:7,6-b′]dithiophene(1a), a mixture of the cis and trans isomers thereof. The gate electrodecan be included in the substrate, in the dielectric layer, and the likethroughout.

FIG. 2 schematically illustrates another TFT configuration 30 comprisedof a substrate 36, a gate electrode 38, a source electrode 40, and adrain electrode 42, an insulating dielectric layer 34, and afunctionalized heteroacene semiconductor layer 32 of5,11-bis(4-phenylethynyl)anthra[2,3-b:6,7-b′]dithiophene/5,11-bis(4-phenylethynyl)anthra[2,3-b:7,6-b′]dithiophene(8a), a mixture of the cis and trans isomers thereof.

FIG. 3 schematically illustrates a further TFT configuration 50comprised of a heavily n-doped silicon wafer 56, which can act as a gateelectrode, a thermally grown silicon oxide dielectric layer 54, thefunctionalized heteroacene semiconductor layer 52 of FIG. 2, on top ofwhich are deposited a source electrode 60 and a drain electrode 62; anda gate electrode contact 64.

FIG. 4 schematically illustrates a TFT configuration 70 comprised ofsubstrate 76, a gate electrode 78, a source electrode 80, a drainelectrode 82, a functionalized heteroacene semiconductor layer 72 ofFIG. 2, and an insulating dielectric layer 74.

Also, other devices not disclosed, especially TFT devices, areenvisioned, reference for example known TFT devices.

In some embodiments of the present disclosure, an optional protectinglayer may be incorporated on top of each of the transistorconfigurations of FIGS. 1, 2, 3 and 4. For the TFT configuration of FIG.4, the insulating dielectric layer 74 may also function as a protectinglayer.

Also disclosed are semiconductors of thiopheneacenes of the followingformula

wherein R and R′ are hydrogen, alkyl, unsaturated alkyl, aryl, alkylsubstituted aryl, unsaturated alkyl substituted aryl, or mixturesthereof, and wherein n represents the number of rings of, for example,equal to or greater than 3, such as from about 3 to about 2,000, andmore specifically, wherein n=5, R′═H, and R=dodycyne.

These novel organic semiconductors, such as for use in TFTs, can beprepared by the following reaction scheme

The final product was greenish and it showed a UV maximum peak at awavelength of 740 nanometers. The UV spectra data for the maximum peakabsorbance at 740 nanometers are listed in Table 1. It showed that thesolution of structure (2) is more stable in the ambient condition thanpentacene.

TABLE 1 UV SPECTRA DATA FOR THE STRUCTURE (2) IN THF Maximum WavelengthTime (Min.) (λ, nm) Absorbance Stability 1 740 1.193  100% 10 740 1.16397.5% 20 740 1.121 94.0% 30 740 1.080 90.5%

In embodiments and with further reference to the present disclosure andthe Figures, the device substrate layer may generally be a siliconmaterial inclusive of various appropriate forms of silicon, a glassplate, a plastic film or a sheet, and the like depending on the intendedapplications. For structurally flexible devices, a plastic substrate,such as for example polyester, polycarbonate, polyimide sheets, and thelike, may be selected. The thickness of the substrate may be, forexample, from about 10 micrometers to over 10 millimeters with aspecific thickness being from about 50 to about 100 micrometers,especially for a flexible plastic sustrate, and from about 1 to about 10millimeters for a rigid substrate, such as glass or silicon.

The insulating dielectric layer, which can separate the gate electrodefrom the source and drain electrodes, and in contact with thesemiconductor layer, can generally be an inorganic material film, anorganic polymer film, or an organic-inorganic composite film. Thethickness of the dielectric layer is, for example, from about 10nometers to about 1 micrometer with a more specific thickness beingabout 100 nometers to about 500 nanometers. Illustrative examples ofinorganic materials suitable as the dielectric layer include siliconoxide, silicon nitride, aluminum oxide, barium titanate, bariumzirconate titanate, and the like; illustrative examples of organicpolymers for the dielectric layer include polyesters, polycarbonates,poly(vinyl phenol), polyimides, polystyrene, poly(methacrylate)s,poly(acrylate)s, epoxy resin, and the like; and illustrative examples ofinorganic-organic composite materials include nanosized metal oxideparticles dispersed in polymers such as polyester, polyimide, epoxyresin and the like. The insulating dielectric layer is generally of athickness of from about 50 nanometers to about 500 nanometers dependingon the dielectric constant of the dielectric material used. Morespecifically, the dielectric material has a dielectric constant of, forexample, at least about 3, thus a suitable dielectric thickness of about300 nanometers can provide a desirable capacitance, for example, ofabout 10⁻⁹ to about 10⁻⁷ F/cm².

Situated, for example, between and in contact with the dielectric layerand the source/drain electrodes is the active semiconductor layercomprised of the functionalized heteroacenes illustrated herein, andwherein the thickness of this layer is generally, for example, about 10nanometers to about 1 micrometer, or about 40 to about 100 nanometers.This layer can generally be fabricated by solution processes, such asspin coating, casting, screen, stamp, or jet printing of a solution ofthe functionalized heteroacenes of the present disclosure.

The gate electrode can be a thin metal film, a conducting polymer film,a conducting film generated from a conducting ink or paste, or thesubstrate itself (for example, heavily doped silicon). Examples of gateelectrode materials include but are not limited to aluminum, gold,chromium, indium tin oxide, conducting polymers, such as polystyrenesulfonate-doped poly(3,4-ethylenedioxythiophene) (PSS/PEDOT), aconducting ink/paste comprised of carbon black/graphite or colloidalsilver dispersion contained in a polymer binder, such as Electrodagavailable from Acheson Colloids Company, and silver filled electricallyconductive thermoplastic ink available from Noelle Industries, and thelike. The gate layer can be prepared by vacuum evaporation, sputteringof metals or conductive metal oxides, coating from conducting polymersolutions or conducting inks, or dispersions by spin coating, casting orprinting. The thickness of the gate electrode layer is, for example,from about 10 nanometers to about 10 micrometers, and a specificthickness is, for example, from about 10 to about 200 nanometers formetal films, and about 1 to about 10 micrometers for polymer conductors.

The source and drain electrode layer can be fabricated from materialswhich provide a low resistance ohmic contact to the semiconductor layer.Typical materials suitable for use as source and drain electrodesinclude those of the gate electrode materials, such as gold, nickel,aluminum, platinum, conducting polymers, and conducting inks. Typicalthickness of this layer is, for example, from about 40 nanometers toabout 1 micrometer with the more specific thickness being about 100 toabout 400 nanometers. The TFT devices contain a semiconductor channelwith a width W and length L. The semiconductor channel width may be, forexample, from about 10 micrometers to about 5 millimeters with aspecific channel width being about 100 micrometers to about 1millimeter. The semiconductor channel length may be, for example, fromabout 1 micrometer to about 1 millimeter with a more specific channellength being from about 5 micrometers to about 100 micrometers.

The source electrode is grounded and a bias voltage of generally, forexample, about 0 volt to about −80 volts is applied to the drainelectrode to collect the charge carriers transported across thesemiconductor channel when a voltage of generally about +10 volts toabout −80 volts is applied to the gate electrode.

Other known materials not recited herein for the various components ofthe TFT devices of the present disclosure can also be selected inembodiments.

Although not desiring to be limited by theory, it is believed that thealkynyl like the ethynyl groups function primarily to minimize or avoidinstability because of exposure to oxygen, and thus increase theoxidative stability of the heteroacenes in solution under ambientconditions, and the alkyl and/or alkylaryl substituents or groups permitthe solubility of these compounds in common solvents, such as ethylenechloride. Also, in embodiments alkyl groups that are unbranched couldfacilitate the formation of layered pi-stacks, a favorable form forcharge transport properties.

The claims, as originally presented and as they may be amended,encompass variations, alternatives, modifications, improvements,equivalents, and substantial equivalents of the embodiments andteachings disclosed herein, including those that are presentlyunforeseen or unappreciated, and that, for example, may arise fromapplicants/patentees and others. Unless specifically recited in a claim,steps or components of claims should not be implied or imported from thespecification or any other claims as to any particular order, number,position, size, shape, angle, color, or material.

1. An electronic device comprising a semiconductive material containinga component of Formula (I)

wherein R represents alkyl, alkoxy, aryl, or heteroaryl; each R₁ and R₂is independently hydrogen (H), alkyl, aryl, a heteroatom containinggroup, cyano, nitro, or a halogen; R₃ and R₄ are independently alkyl,aryl, a heteroatom containing group, or a halogen; x and y represent thenumber of groups; Z represents sulfur, oxygen, selenium, or NR′ whereinR′ is hydrogen, alkyl, or aryl; and n and m represent the number ofrepeating units.
 2. A device in accordance with claim 1 wherein R isaryl with from about 6 to about 48 carbon atoms.
 3. A device inaccordance with claim 1 wherein R is alkyl with from about 1 to about 25carbon atoms.
 4. A device in accordance with claim 1 wherein R is aheteroaryl with from about 7 to about 37 carbon atoms.
 5. A device inaccordance with claim 1 wherein at least one of R₁ and R₂ is hydrogen.6. A device in accordance with claim 1 wherein at least one of R₁ and R₂is alkyl.
 7. A device in accordance with claim 1 wherein at least one ofR₁ and R₂ is aryl.
 8. A device in accordance with claim 1 wherein atleast one of R₁ and R₂ is halogen.
 9. A device in accordance with claim1 wherein at least one of R₁ and R₂ is cyano or nitro.
 10. A device inaccordance with claim 1 wherein at least one of R₃ and R₄ is alkyl. 11.A device in accordance with claim 1 wherein at least one of R₃ and R₄ isaryl.
 12. A device in accordance with claim 1 wherein said heteroatomcontaining group is dialkylamine, diarylamine, alkoxy, trialkylsilyl ortriarylsilyl.
 13. A device in accordance with claim 1 wherein saidheteroatom containing group is thienyl, pyridyl, trialkylsilyl,triarylsilyl, or alkoxyalkoxyaryl.
 14. A device in accordance with claim1 wherein at least one of R₁, R₂, R₃, R₄ and R is alkyl.
 15. A device inaccordance with claim 1 wherein Z is sulfur, oxygen, or selenium.
 16. Adevice in accordance with claim 1 wherein Z is NR′ wherein R′ is alkyl,or aryl.
 17. A device in accordance with claim 1 wherein m is a numberof from 0 to about
 3. 18. A device in accordance with claim 1 wherein mis
 2. 19. A device in accordance with claim 1 wherein m is
 1. 20. Adevice in accordance with claim 1 wherein n is a number of from 0 toabout
 3. 21. A device in accordance with claim 1 wherein n is 1 or 2.22. A device in accordance with claim 1 wherein x is a number of from 0to about
 12. 23. A device in accordance with claim 1 wherein x is anumber of from 0 to about
 6. 24. A device in accordance with claim 1wherein y is a number of from 0 to about
 12. 25. A device in accordancewith claim 1 wherein y is a number of from 0 to about
 4. 26. A device inaccordance with claim 1 wherein R is aryl with 6 to about 36 carbonatoms; R₁ and R₂ are hydrogen; x=y=0; m and n are equal, and m is 1 or2.
 27. A thin film transistor comprised of a substrate, a gateelectrode, a gate dielectric layer, a source electrode and a drainelectrode, and in contact with the source/drain electrodes and the gatedielectric layer a semiconductor layer comprising a functionalizedheteroacene of the formula

wherein R is alkyl, alkoxy, aryl, or heteroaryl; each R₁ and R₂ isindependently hydrogen (H), alkyl, aryl, cyano, nitro, a heteroatomcontaining group or a halogen; R₃ and R₄ are independently alkyl, aryl,a heteroatom containing group, or a halogen; x, and y represent thenumber of groups; Z represents sulfur, oxygen, selenium, or NR′ whereinR′ is hydrogen, alkyl, or aryl; and m and n represent the number ofrings.
 28. A device in accordance with claim 27 wherein alkyl is ethyl,propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl,dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl,octadecyl, nonadecyl, or eicosanyl.
 29. A device in accordance withclaim 27 wherein aryl is phenyl, tolyl, butylphenyl, pentylphenyl,hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl,undecylphenyl, dodecylphenyl, tridecylphenyl, tetradecylphenyl,pentadecylphenyl, hexadecylphenyl, heptadecylphenyl, octadecylphenyl,naphthyl, methylnaphthyl, ethylnaphthyl, propylnaphthyl, butylnaphthyl,pentylnaphthyl, hexylnaphthyl, heptylnaphthyl, octylnaphthyl,nonylnaphthyl, decylnaphthyl, undecylnaphthyl, dodecylnaphthyl, anthryl,methylanthryl, ethylanthryl, propylanthryl, butylanthyl, pentylanthryl,octylanthryl, nonylanthryl, decylanthryl, undecylanthryl, ordodecylanthryl.
 30. A device in accordance with claim 27 whereinheteroaryl is thienyl, methylthienyl, ethylthienyl, propylthienyl,butylthienyl, hexylthienyl, heptylthienyl, octylthienyl, nonylthienyl,decylthienyl, undecylthienyl, dodecylthienyl, bithiophenyl,methylbithiophenyl, ethylbithiophenyl, propylbithiophenyl,propylbithiophenyl, butylbithiophenyl, pentylbithiophenyl,hexylbithiophenyl, heptylbithiophenyl, octylbithiophenyl,nonylbithiophenyl, decylbithiophenyl, undecylbithiophenyl,dodecylbithiophenyl, pyridyl, methylpyridyl, ethylpyridyl,propylpyridyl, butylpyridyl, pentylpyridyl, hexylpyridyl, heptylpyridyl,octylpyridyl, nonylpyridyl, decylpyridyl, undecylpyridyl,dodecylpyridyl, thiazolyl, methylthiazolyl, ethylthiazolyl,propylthiazolyl, butylthiazolyl, pentylthiazolyl, hexylthiazolyl,heptylthiazolyl, octylthiazolyl, nonylthiazolyl, decylthiazolyl,undecylthiazolyl, or dodecylthiazolyl.
 31. A device in accordance withclaim 27 wherein the functionalized heteroacene is selected from thegroup consisting of the following formulas

wherein R₅ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl,octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,hexadecyl, heptadecyl, or octadecyl; trifluoromethyl, fluoroethyl,perflucropropyl, perfluorobutyl, pertluoropentyl, pert luorohexyl,perfluoroheptyl, pertluorooctyl, perfluorononyl, pereluorodecyl, pertluoroundecyl, or perfluorododecyl; phenyl, methylphenyl (tolyl),ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl,heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl,dodecylphenyl, tridecylphenyl, tetradecylphenyl, pentadecylphenyl,hexadecylphenyl, heptadecylphenyl, octadecylphenyl,trifluoromethylphenyl, fluoroethylphenyl, perluoropropylphenyl,perflucrobutylphenyl, pertluoropentylphenyl, pertluorohexylphenyl,pertluoroheptylphenyl, pertluorooctylphenyl, perfluorononylphenyl,perfluorodecylphenyl, pertluoroundecylphenyl, or pertluorododecylphenyl.32. A device in accordance with claim 27 wherein said substrate is aplastic sheet of a polyester, a polycarbonate, or a polylmide; and saidgate, source, and drain electrodes are each independently comprised ofsilver, gold, nickel, aluminum, chromium, platinum, or indium titaniumoxide, or a conductive polymer, and said gate dielectric layer iscomprised of inorganic nitrides or oxides, or organic polymers, siliconnitride, silicon oxide.
 33. A device in accordance with claim 27 whereinthe functionalized heteroacene comprises a mixture of the cis and transisomers of said formula.
 34. A thin film transistor comprised of asubstrate, a gate electrode, a gate dielectric layer, a sourceelectrode, a drain electrode and a layer containing at least onefunctionalized heteroacene selected from the group consisting of theformulas/structures:

wherein R₅ is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl,octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,hexadecyl, heptadecyl, or octadecyl; trifluoromethyl, fluoroethyl,perfluoropropyl, perfluorobutyl, perfluoropentyl, pertluorohexyl,periluoroheptyl, perfluorooctyl, perfluorononyl, perfluorodecyl,perfluoroundecyl, or perfluorododecyl; phenyl, methylphenyl (tolyl),ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl,heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl,dodecylphenyl, tridecylphenyl, tetradecylphenyl, pentadecylphenyl,hexadecylphenyl, heptadecylphenyl, octadecylphenyl,trifluoromethylphenyl, fluoroethylphenyl, perflucropropylphenyl,perfluorobutylphenyl, perfluoropentylphenyl, pertluorohexylphenyl,pertluoroheptylphenyl, perfluorooctylphenyl, perfluorononylphenyl,perfluorodecylphenyl, perfluoroundecylphenyl, or perflucrododecylphenyl;and wherein X is F, Cl, Br, CN, or NO₂.